Commit Message

On ARM, manipulating live page tables is cumbersome since the architecture
mandates the use of break-before-make, i.e., replacing a block entry with
a table entry requires an intermediate step via an invalid entry, or TLB
conflicts may occur.
Since it is not generally feasible to decide in the page table manipulation
routines whether such an invalid entry will result in those routines
themselves to become unavailable, and since UEFI uses an identity mapping
anyway, it is far simpler to just disable the MMU, perform the page table
manipulations, flush the TLBs and re-enable the MMU.
Contributed-under: TianoCore Contribution Agreement 1.0
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
---
ArmPkg/Library/ArmLib/AArch64/AArch64Mmu.c | 39 ++++++++++++++++++++
1 file changed, 39 insertions(+)
--
2.5.0
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